Polycarbonate having improved hydrolytic stability

This application is a continuation in part of our copending application Ser. No. 866,881 filed Jan. 4, 1978 now abandoned which itself is a continuation of application Ser. No. 777,205 filed Mar. 14, 1977, now abandoned, which in turn is a continuation of our application Ser. No. 659,316, filed Feb. 19, 1976, now abandoned.

1. Field of the Invention

This invention relates to polycarbonates and more particularly to polycarbonates having improved hydrolytic stability.

2. Description of the Prior Art

Polycarbonates derived from reactions involving organic dihydroxy compounds and carbonic acid derivatives have found extensive commercial application because of their excellent mechanical and physical properties. These thermoplastic polymers are particularly suited for the manufacture of molded products where impact strength, rigidity, toughness, thermal and dimensional stability as well as excellent electrical properties are required.

Further in many applications, especially those requiring extensive service in the presence of heat and light, polycarbonates are used because of their resistance to these constant conditions. The polycarbonates resistance to extensive light and heat is in many instances attributable to stabilizers which prevent deterioration of optical and molecular properties. Among the most extensively used stabilizers are the neutral esters of phosphorous acid including the alkyl and aryl phosphites and the oxetane phosphites. More extensive discussions involving some phosphite stabilizers can be found in U.S. Pat. No. 3,794,629. Although these stabilizers are effective in protecting the polycarbonate from heat and light they cause the polycarbonate to deteriorate, due to hydrolysis, when exposed to water under elevated temperatures.

In some applications polycarbonates are provided with enhanced flame retardant characteristics by using aromatic diols with bromine or chlorine atoms which have a tendency to free radically dissociate and degrade the polycarbonate. To prevent this degradation phosphites have also been added. However, the phosphites, just as in the case of the non-halogenated polycarbonates have a tendency to make the polycarbonate more susceptible to hydrolytic attack.

Thus in accordance with the present invention polycarbonates are provided having improved hydrolytic stability over conventional stabilizers yet with the other desirable properties of the polycarbonate left substantially unmodified.

A polycarbonate is provided with enhanced hydrolytic stability which is comprised of an effective amount of a carboxylic acid salt of cadmium and a polycarbonate resin.

When used herein "polycarbonate resin" means the neat resin without additives; "Polycarbonate" means both the formulated polycarbonate resin with additives therein and also the final molded plastic product.

The polycarbonate resins useful in practice of the invention are those having a weight average molecular weight between 10,00 and 200,000 and more preferably a melt flow rate range of 1 to 24 g/10 min at 300° C. (ASTM 1238) and are produced by reacting di-(monohydroxyaryl)alkanes or dihydroxybenzenes and substituted dihydroxybenzenes with derivatives of the carbonic acids such as carbonic acid diester, phosgene, bis-chloro-carbonic acid esters of di-(monohydroxyaryl)-alkanes and the bis-chloro-carbonic acid esters of the dihydroxybenzenes and the substituted dihydroxybenzenes.

The two aryl residues of the di-(monohydroxyaryl)alkanes applied according to the invention can be alike or different. The aryl residues can also carry substituents which are not capable of reacting in the conversion into polycarbonates, such as halogen atoms or alkyl groups, for example, the methyl, ethyl, propyl or tert-butyl groups. The alkyl residue of the di-(monohydroxyaryl)alkanes linking the two benzene rings can be an open chain or a cycloaliphatic ring and may be substituted if desired, for example by an aryl residue.

Suitable di-(monohydroxyaryl)-alkanes are for example (4,4'-dihydroxy-diphenyl)-methane, 2,2'-(4,4'-dihydroxy-diphenyl)-propane, 1,1-(4,4'-dihydroxy-diphenyl)cyclohexane, 1,1-(4,4'-dihydroxy-3,3'-dimethyl-diphenyl)cyclohexane, 1,1-(2,2'-dihydroxy-4,4'-dimethyl-diphenyl)butane, 2,2-(2,2'-dihydroxy-4,4'-di-tert.-butyl-diphenyl)propane or 1,1'-(4,4'-dihydroxy-diphenyl)-1-phenyl-ethane, furthermore methane derivatives which carry besides two hydroxyaryl groups an alkyl residue with at least two carbon atoms and a second alkyl residue with one or more carbon atoms, such as 2,2-(4,4'-dihydroxy-diphenyl)-butane, 2,2-(4,4'-dihydroxy-diphenyl)-pentane (melting point 149°-150° C.), 3,3-(4,4'-dihydroxy-diphenyl)-pentane, 2,2-(4,4'-dihydroxy-diphenyl)-hexane, 3,3-(4,4'-dihydroxydiphenyl)-hexane, 2,2-(4,4'-dihydroxy-diphenyl)-4-methylpentane, 2,2-(4,4'-dihydroxy-diphenyl)-heptane, 4,4-(4,4'-dihydroxy-diphenyl)-heptane (melting point 148°-149° C.) or 2,2-(4,4'-dihydroxy-diphenyl)-tri-decane. Suitable di-(monohydroxyaryl)-alkanes, the two aryl residues of which are different are, for example, 2,2-(4,4'-dihydroxy-3'-methyl-diphenyl)-propane and 2,2-(4,4'-dihydroxy-3-methyl-3'-isopropyl-diphenyl)-butane. Suitable di-(monohydroxyaryl)-alkanes, the aryl residues of which carry halogen atoms are for instance 2,2-(3,5,3'5'-tetrachloro-4,4'-dihydroxy-diphenyl)-propane, 2,2-(3,5,3'5'-tetrabromo-4,4'-dihydroxy-diphenyl)-propane, (3,3'-dichloro-4,4'-dihydroxy-diphenyl)-methane and 2,2'-dihydroxy-5,5'-difluoro-diphenyl-methane. Suitable di-(monohydroxyaryl)-alkanes, the alkyl residue of which, linking the two benzene rings, is substituted by an aryl residue are for instance (4,4'-dihydroxydiphenyl)-phenyl-methane and 1,1-(4,4'-dihydroxy-diphenyl)-1-phenyl-ethane.

Suitable dihydroxybenzenes and substituted dihydroxybenzenes are hydroquinone, resorcinol, pyrocatecol, methyl hydroquinone and the like. Other suitable dihydroxyaromatic compounds are 4,4'-dihydroxydiphenyl, 2,2'-dihydroxy-diphenyl, dihydroxynaphthalene, dihydroxyanthracene and compounds represented by the structural formula: ##STR1## wherein X is ##STR2##

In order to obtain special properties, mixtures of various di-(monohydroxyaryl)-alkanes can also be used, thus mixed polycarbonate resins are obtained. By far the most useful polycarbonate resins are those based on 4,4'-dihydroxy-diaryl methanes and more particularly bisphenol A [2,2-(4,4'dihydroxy-diphenyl)-propane]. Thus when flame retardant characteristics are to be imparted to the basic polycarbonate resin, a mixture of bisphenol A and tetrabromobisphenol A [2,2-(3,5,3'5'-tetrabromo-4,4'dihydroxy-diphenyl)-propane] is utilized when reacting with phosgene or a like carbonic acid derivative.

The polycarbonates resins are prepared by methods known to those skilled in the art and more particularly by methods disclosed in U.S. Pat. Nos. 3,028,365, 2,999,846, 3,248,414, 3,153,008, 3,215,668, 3,187,065, 2,970,137, 2,991,273 and 2,999,835 all incorporated herein by reference.

In some uses, pigments may be added to the polycarbonate to form opaque colored molded products. The pigments used to opacify and color the polycarbonate are those conventionally known to skilled artisans for use in high molecular weight thermoplastic pigmentation. By far titanium dioxide is the most preferred pigment to opacify and whiten molded articles because of its high index of refraction, extreme whiteness and brightness. However, other white pigments such as lithopone, zinc sulfide, zinc oxide, antimony trioxide, and the like may be used. To impart color (other than white) to the polycarbonate pigments such as red lead, cuprous oxide, cadmium reds, cinnabar, antimony vermilion (red and brown pigments); zinc yellow, chrome yellows and oranges, cadmium yellow, antimony yellow, (orange and yellow pigments); chrome greens, chrome oxide greens (green pigments); cobalt blue, lampblacks, vegetable blacks, animal blacks (black pigments) and the like may be used.

In addition to the inorganic pigments, recited above, organic pigments may be used such as pigment chlorine, lithol fast yellow, touidine red, permanent orange and the like. Dyes may be added to impart color to the polycarbonate such as the phthalocyanies, the anthraquinones and the like.

The cadmium salts homogeneously incorporated in the polycarbonate which are useful in the practice of the invention are those which are soluble in the polycarbonate resin and readily incorporated therein and based on carboxylic acids and cadmium. In particular, cadmium 2-ethylhexanoate, cadmium laurate, cadmium octoate and cadmium acetate have found the most extensive utility for providing increased hydrolytic stability to the polycarbonate in the practice of the invention.

When cadmium 2-ethylhexanoate is used in the practice of the invention preferably a 66 weight percent solid solution of cadmium 2-ethylhexanoate is incorporated into the polycarbonate at a level of 0.01 to 0.1 percent by weight based on the weight of the polycarbonate resin cadmium laurate is also added to the polycarbonate in an amount between 0.01 and 0.1% by weight based on the weight of the polycarbonate resin.

The invention will be further illustrated by way of the following examples.

A polycarbonate resin which was the reaction product of bisphenol A and phosgene having a melt flow at 300° C. of 3 to 6 grams/10 min. (ASTM D1238) was tinted with 0.00093 g of an anthraquinone blue dye per pound of polycarbonate resin and 0.00064 g of an anthraquinone violet blue dye per pound of polycarbonate resin; 0.05 percent by weight, based on the polycarbonate resin of a 66 weight percent solution of cadmium 2-ethylhexanoate was incorporated into the polycarbonate. The polycarbonate resin, the cadmium 2-ethylhexanoate and the tint were tumble blended and then extruded into pellets; 1/8" sample bars were prepared for impact, tensile and elongation testing. Further the impact and tensile bars were tested for hydrolytic stability. The test results for hydrolytic stability are reported on table I. The samples were tested after oven aging at 130° C. for tensile strength and elongation; the results of the oven aging tests are reported on table II. Tests for optical and melt stability were conducted by molding specimens at 520° F. and 700° F. and by aging the polycarbonate at 375° C. The results of the optical and melt stability tests are reported on table III. The effect of hydrolysis on aging the molded samples at 82° C. in water were conducted; the results of these tests are reported on table IV. Oven aging tests at 130° C. were conducted to determine the effect of such aging on optical properties; the results of such tests are reported on table V. In all of the examples the percentage of cadmium 2-ethylhexanoate shown is that of a 66 percent solids solution thereof.

Example I was repeated except that the stabilizer and pigmentation were varied. The following formulations keyed to the specific examples show the constituents of the particular polycarbonate.

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Formulation

______________________________________

Polycarbonate resin of Example I

II 0.00093g/lb polycarbonate resin of

anthraquinone blue dye

0.00064g/lb polycarbonate resin of

anthraquinone violet dye

0.05% phenylneopentyl phosphite

Polycarbonate resin of Example I

III 0.00093g/lb polycarbonate resin of

anthraquinone blue dye

0.00064g/lb polycarbonate resin of

anthraquinone violet dye

0.08% tris(3-ethyl-3-methylol oxetane) phosphite

Polycarbonate resin of Example I

IV 0.00093g/lb polycarbonate resin of

anthraquinone blue dye

0.00064g/lb polycarbonate resin of

anthraquinone violet dye

1.36g/lb of polycarbonate resin of hydroxy-

benzotriazole

0.05% cadmium 2-ethylhexanoate solution

Polycarbonate resin of Example I

V 0.00093g/lb polycarbonate resin of

anthraquinone blue dye

0.00064g/lb polycarbonate resin of

anthraquinone violet dye

1.36g/lb of polycarbonate resin of hydroxy-

benzotriazole

0.05% phenylneopentyl phosphite

Polycarbonate resin of Example I

VI 0.00093g/lb polycarbonate resin of

anthraquinone blue dye

0.00064g/lb polycarbonate resin of

anthraquinone violet dye

1.36g/lb polycarbonate resin of hydroxybenzotriazole

0.08% tris(3-ethyl-3-methylol oxetane)-phosphite

Polycarbonate resin of Example I

VII 0.00093g/lb polycarbonate resin of

anthraquinone blue dye

0.00064g/lb polycarbonate resin of

anthraquinone violet dye

0.5% the cerotic acid ester of ceryl alcohol

1.36g/lb polycarbonate resin of hydroxybenzotriazole

0.05% cadmium 2-ethylhexanoate solution

Polycarbonate resin of Example I

VIII 0.00093g/lb polycarbonate resin of

anthraquinone blue dye

0.00064g/lb polycarbonate resin of

anthraquinone violet dye

0.5% the cerotic acid ester of ceryl alcohol

1.36g/lb polycarbonate resin of hydroxybenzotriazole

0.05% phenylneopentyl phosphite

Polycarbonate resin of Example I

IX 0.00093g/lb polycarbonate resin of

anthraquinone blue dye

0.00064g/lb polycarbonate resin of

anthraquinone violet dye

0.5% of the cerotic acid ester of ceryl alcohol

1.36g/lb of hydroxybenzotriazole

0.08% tris(3-ethyl-3-methylol-oxetane) phosphite

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The cerotic acid ester of ceryl alcohol is incorporated into the polycarbonate as a mold release in accordance with the teachings of U.S. Pat. No. 3,836,499 incorporated herein by reference.

The hydroxybenzotriazole is a stabilizer for resistance to ultraviolet light. The polycarbonates of Examples II through IX were prepared and tested in accordance with Example I. The results of the tests are reported in the following tables.

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THEREIN DURING AGING IN WATER AT 82° C.

__________________________________________________________________________

Stabilizer

Tensile Yield

Tensile Ult.

Elong.

Elong.

Impact

Stabilizer

Concn. %

Str. psi

Str. psi

Yield %

Ult. %

Ft.-Lbs.

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Control (Unaged)

I cadmium 2-ethyl-

0.05 9000 9200 8 100 20.68

hexanoate

II phenylneopentyl

0.05 9133 9400 8 102 18.91

phosphite

III oxetane phosphite.sup.1

0.08 9400 9400 8 100 19.06

IV cadium 2-ethyl-

0.05 8933 9000 8 100 18.34

hexanoate

V phenylneopentyl

0.05 9300 9000 17.28

phosphite

VI oxetane phosphite

0.08 9867 9867 3-10

103 17.10

VII cadmium 2-ethyl-

0.05 9300 9617 10 106 19.06

hexanoate

VIII phenylneopentyl

0.05 9600 9600 11 102 18.25

phosphite

IX oxetane phosphite

0.08 9867 9867 11 102 17.51

3 Days

I cadmium 2-ethyl-

0.05 9200 9200 6 20-80

16.95

hexanoate

II phenylneopentyl

0.05 9800 9800 6 6- 95

11.46

phosphite

III oxetane phosphite.sup.1

0.08 10100 10100 6 7-45

15.74

IV cadmium 2-ethyl-

0.05 9800 9800 6 45-90

12.3

hexanoate

V phenylneopentyl

0.05 10000 10000 7 90 2.58

phosphite

VI oxetane phosphite

0.08 10500 10500 6 7.45

2.92

VII cadmium 2-ethyl-

0.05 9600 9600 7 20-105

2.22

hexanoate

VIII phenylneopentyl

0.05 10000 10000 7 65 1.97

phosphite

IX oxetane phosphite

0.08 10300 10300 5 5 2.09

6 Days

I cadmium 2-ethyl-

0.05 9600 9600 6 5-70

15.61

hexanoate

II phenylneopentyl

0.05 9900 9900 5 20-90

2.54

phosphite

III oxetane phosphite.sup.1

0.08 10200 10200 6 8 15.52

IV cadmium 2-ethyl-

0.05 10000 10000 6 35-100

2.68

hexanoate

V phenylneopentyl

0.05 10200 10200 7 40 1.95

phosphite

VI oxetane phosphite

0.08 8300 8300 6 7 2.27

VII cadmium 2-ethyl-

0.05 9700 9700 6 6-60

2.06

hexanoate

VIII phenylneopentyl

0.05 10200 10200 7 80 1.52

phosphite

IX oxetane phosphite

0.08 10600 10600 5 15-60

1.68

12 Days

I cadmium 2-ethyl-

0.05 9500 9500 8 20-95

15.74

hexanoate

II phenylneopentyl

0.05 9900 9900 8 20 1.75

phosphite

III oxetane phosphite.sup.1

0.08 10100 10100 8 8 2.1

IV cadmium 2-ethyl-

0.05 4300 4300 4 4 Fail

hexanoate

V phenylneopentyl

0.05 4500 4500 4 4 Fail

phosphite

VI oxetane phosphite

0.08 1200 1200 <2 <2 Fail

VII cadmium 2-ethyl-

0.05 9600 9600 8 8-35

Fail

hexanoate

VIII phenylneopentyl

0.05 5800 5800 4 4 Fail

phosphite -IX

oxetane phosphite

0.08 3000 3000 2 2 Fail

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Stabilizer

Tensile Yield

Tensile Ult.

Elong.

Elong.

Impact

Stabilizer

Concn. %

Str. psi

Elong. psi

Yield psi

Ult. %

Ft.-lbs.

__________________________________________________________________________

24 Days

I cadmium 2-ethyl-

0.05 9800 7300-9800

5 5-40

11.3

hexanoate 66% high

II phenylneopentyl

0.05 10150 7300-10200

5 5-20

0.6

phosphite 67% low 66% high

III oxetane phosphite.sup.1

0.08 -- 10567 2 1.6

IV cadmium 2-ethyl-

0.05 -- 1900 -- 1 Fail

hexanoate

V phenylneopentyl

0.05 -- 2000 -- 1 Fail

phosphite

VI oxetane phosphite

0.08 -- 800 -- 1 Fail

VII cadmium 2-ethyl-

0.05 4400 4400 <1 1 Fail

hexanoate

VIII phenylneopentyl

0.05 -- 1867 -- 1 Fail

phosphite

IX oxetane phosphite

0.08 -- 1200 -- 1 Fail

__________________________________________________________________________

.sup.1 oxetane phosphite is tris(3ethyl-3-methylol oxetane)phosphite.

__________________________________________________________________________

THEREIN DURING OVEN AGING AT 130° C.

Stabilizer

Tensile Yield

Tensile Ult.

Elong.

Elong.

Stabilizer

Concn. %

Str. psi

Str. psi

Yield %

Ult. %

__________________________________________________________________________

Control

I cadmium 2-ethyl-

0.05 9000 9200 8 100

hexanoate

II phenylneopentyl

0.05 8933 9000 8 100

phosphite

III oxetane phosphite.sup.1

0.08 9300 9617 10 106

IV cadmium 2-ethyl-

0.05 9133 9400 8 102

hexanoate

V phenylneopentyl

0.05 9300 9000 8 100

phosphite

VI oxetane phosphite

0.08 9600 9600 11 102

VII cadmium 2-ethyl-

0.05 9400 9400 8 100

hexanoate

VIII phenylneopentyl

0.05 9867 9867 8 103

phosphite

IX oxetane phosphite

0.08 9867 9867 11 102

3 Days

I cadmium 2-ethyl-

0.05 10600 10600 8 75

hexanoate

II phenylneopentyl

0.05 10600 10600 8 90

phosphite

III oxetane phosphite.sup.1

0.08 -- -- -- --

IV cadmium 2-ethyl-

0.05 11000 11000 8 30-105

hexanoate

V phenylneopentyl

0.05 11000 11000 8 10-70

phosphite

VI oxetane phosphite

0.08 11000 11000 8 40-105

VII cadmium 2-ethyl-

0.05 11400 11400 8 20

hexanoate

VIII phenylneopentyl

0.05 11300 11300 8 25

phosphite

IX oxetane phosphite

0.08 11200 11200 8 10-55

6 Days

I cadmium 2-ethyl-

0.05 11000 11000 9 30-100

hexanoate

II phenylneopentyl

0.05 7666 11033 9 42

phosphite

III oxetane phosphite.sup.1

0.08 8000 11000 9 90

IV cadmium 2-ethyl-

0.05 8000 11433 10 20-50

hexanoate

V phenylneopentyl

0.05 8033 11466 9 45

phosphite

VI oxetane phosphite

0.08 7966 11200 9 35-105

VII cadmium 2-ethyl-

0.05 11933 11933 11 14

hexanoate

VIII phenylneopentyl

0.05 10400 11266 10 20

phosphite

IX oxetane phosphite

0.08 8233 11233 8 25-70

12 Days

I cadmium 2-ethyl-

0.05 11300 11300

7 30-75

hexanoate

II phenylneopentyl

0.05 11400 11400 8 20

phosphite

III oxetane phosphite.sup.1

0.08 11400 11400 8 10-85

IV cadmium 2-ethyl-

0.05 11500 11500 7 10-75

hexanoate

V phenylneopentyl

0.05 11500 11500 8 10-50

phosphite

VI oxetane phosphite

0.08 12000 12000 8 10-50

VII cadmium 2-ethyl-

0.05 11800 11800 7 38

hexanoate

VIII phenylneopentyl

0.05 11500 11500 7 22

phosphite

IX oxetane phosphite

0.08 11800 11800 8 10-25

24 Days

I cadmium 2-ethyl-

0.05 10800 10800 8 88

hexanoate

II phenylneopentyl

0.05 10800 10800 8 15

phosphite

III oxetane phosphite.sup.1

0.08 10400 10400 8 45

IV cadmium 2-ethyl-

0.05 10900 10900 8 50-105

hexanoate

V phenylneopentyl

0.05 10900 10900 7 40-85

phosphite

VI oxetane phosphite

0.08 11100 11100 8 11-75

VII cadmium 2-ethyl-

0.05 11200 11200 7 7-75

hexanoate

VIII phenylneopentyl

0.05 11600 11600 8 11

phosphite

IX oxetane phosphite

0.08 11400 11400 8 12

__________________________________________________________________________

.sup.1 oxetane phosphite is tris(3ethyl-3-methylol oxetane)phosphite.

__________________________________________________________________________

700° F.

Stabilizer

520° F. Molding

Molding

Irradiation

Melt Stability

Stabilizer

Concn. %

Y %

YI % Haze

Y %

YI at 375° C. APHA

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color

I cadmium 2-

0.05 84.31

0.68

1.06 84.79

2.38

83.89

10.43

900

ethylhexanoate

II phenyl- 0.05 84.85

1.49

1.18 83.70

2.88

84.35

12.09

800-900

neopentyl

phosphite

III oxetane 0.08 85.26

-0.86 85.61

-0.41

84.20

9.49

>1000

phosphite.sup.1

IV cadmium 2-

0.05 84.32

1.10

1.2 84.36

3.17

83.15

4.65

>1000

ethylhexanoate

V phenyl- 0.05 85.32

1.51

1.2 85.28

3.41

84.33

6.06

>1000

neopentyl

phosphite

VI oxetane 0.08 85.23

-0.45

1.0 84.01

3.49

84.42

3.50

>1000

phosphite

VII cadmium 2-

0.05 80.19

2.53

1.08 79.82

5.22

80.99

6.09

>>1000

ethylhexanoate

VIII phenyl- 0.05 84.59

0.22

1.20 83.98

2.18

84.09

4.35

>>1000

neopentyl

phosphite

IX oxetane 0.08 84.83

-0.96

1.20 82.84

5.06

83.78

3.13

>>1000

phosphite

__________________________________________________________________________

.sup.1 oxetane phosphite is tris(3ethyl-3-methylol oxetane) phosphite.

______________________________________

ON AGING IN WATER AT 82° C.

Ex-

ample Stabilizer Concn. Y % YI Haze %

______________________________________

Unaged

I cadmium 2-ethyl-

(0.05%) 84.31

0.68 1.06

hexanoate

II phenylneopentyl

(0.05%) 84.85

1.49 1.18

phosphite

III oxetane phosphite.sup.1

(0.08%) 85.26

-0.86

IV cadmium 2-ethyl-

(0.05%) 84.32

1.10 1.2

hexanoate

V phenylneopentyl

(0.05%) 85.32

1.51 1.2

phosphite

VI oxetane phosphite

(0.08%) 85.23

-0.45 1.0

3 Days

I cadmium 2-ethyl-

(0.05%) 83.91

1.20 1.70

hexanoate

II phenylneopentyl

(0.05%) 84.82

1.78 1.0

phosphite

III oxetane phosphite.sup.1

(0.08%) 85.09

-0.81 2.0

IV cadmium 2-ethyl-

(0.05%) 83.97

1.19 3.0

hexanoate

V phenylneopentyl

(0.05%) 84.66

1.87 1.6

phosphite

VI oxetane phosphite

(0.08%) 85.22

-0.59 1.4

6 Days

I cadmium 2-ethyl-

(0.05%) 84.86

1.29 1.60

hexanoate

II phenylneopentyl

(0.05%) 85.72

2.08 1.7

phosphite

III oxetane phosphite.sup.1

(0.08%) 85.99

- 0.37

1.6

IV cadmium 2-ethyl-

(0.05%) 84.85

1.47 1.5

hexanoate

V phenylneopentyl

(0.05%) 84.80

1.97 1.9

phosphite

VI oxetane phosphite

(0.08%) 85.72

-0.27 1.7

12 Days

I cadmium 2-ethyl-

(0.05%) 84.35

1.23 1.16

hexanoate

II phenylneopentyl

(0.05%) 85.15

2.12 1.62

phosphite

III oxetane phosphite.sup.1

(0.08%) 85.32

-0.54 1.77

IV cadmium 2-ethyl-

(0.05%) -- -- --

hexanoate

V phenylneopentyl

(0.05%) 84.96

2.06 1.52

phosphite

VI oxetane phosphite

(0.08%) 85.22

-0.38 0.84

24 Days

I cadmium 2-ethyl-

(0.05%) 83.98

1.56 3.1

hexanoate

II phenylneopentyl

(0.05%) 83.95

3.45 4.7

phosphite

III oxetane phosphite.sup.1

(0.08%) 84.66

0.62 5.1

IV cadmium 2-ethyl-

(0.05%) 83.39

1.60 2.4

hexanoate

V phenylneopentyl

(0.05%) 83.64

4.21 4.9

phosphite

VI oxetane phosphite

(0.08%) 84.53

0.80 3.3

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.sup.1 oxetane phosphite is tris(3ethyl-3-methylol oxetane) phosphite.

______________________________________

DURING OVEN AGING AT 130° C.

Ex-

ample Stabilizer Concn. Y % YI Haze %

______________________________________

Unaged

I cadmium 2-ethyl-

(0.05%) 84.31

0.68 1.06

hexanoate

II phenylneopentyl

(0.05%) 84.85

1.49 1.18

phosphite

III oxetane phosphite.sup.1

(0.08%) 85.26

-0.86 1.42

IV cadmium 2-ethyl-

(0.05%) 84.32

1.10 1.2

hexanoate

V phenylneopentyl

(0.05%) 85.32

1.51 1.2

phosphite

VI oxetane phosphite

(0.08%) 85.23

-0.45 1.0

3 Days

I cadmium 2-ethyl-

(0.05%) 84.17

1.35 1.13

hexanoate

II phenylneopentyl

(0.05%) 84.62

2.00 1.48

phosphite

III oxetane phosphite.sup.1

(0.08%) 85.49

-0.73 1.01

IV cadmium 2-ethyl-

(0.05%) 83.63

1.48 1.70

hexanoate

V phenylneopentyl

(0.05%) 84.92

2.01 1.21

phosphite

VI oxetane phosphite

(0.08%) 85.07

-0.64 1.32

6 Days

I cadmium 2-ethyl-

(0.05%) 84.17

1.51 1.2

hexanoate

II phenylneopentyl

(0.05%) 83.05

2.27 1.6

phosphite

III oxetane phosphite.sup.1

(0.08%) 85.48

-0.69 1.4

IV cadmium 2-ethyl-

(0.05%) 84.05

1.61 1.9

hexanoate

V phenylneopentyl

(0.05%) 84.74

2.28 1.8

phosphite

VI oxetane phosphite

(0.08%) 85.16

-0.54 1.3

12 Days

I cadmium 2-ethyl-

(0.05%) 82.88

2.02 --

hexanoate

II phenylneopentyl

(0.05%) 83.64

3.09 --

phosphite

III oxetane phosphite.sup.1

(0.08%) 84.37

-0.76 --

IV cadmium 2-ethyl-

(0.05%) 82.89

2.17 --

hexanoate

V phenylneopentyl

(0.05%) 82.69

4.03 --

phosphite

VI oxetane phosphite

(0.08%) 83.78

-0.33 --

24 Days

I cadmium 2-ethyl-

(0.05%) 82.86

2.56 2.7

hexanoate

II phenylneopentyl

(0.05%) 80.97

5.87 3.5

phosphite

III oxetane phosphite.sup.1

(0.08%) 84.20

3.89 2.8

IV cadmium 2-ethyl-

(0.05%) 82.01

3.21 3.4

hexanoate

V phenylneopentyl

(0.05%) 79.66

8.49 3.4

phosphite

VI oxetane phosphite

(0.08%) 83.71

0.50 3.9

______________________________________

.sup.1 oxetane phosphite is tris(3ethyl-3-methylol oxetane) phosphite.

In table I the data show the cadmium 2-ethylhexanoate stabilized polycarbonate to have improved elongation and impact properties over polycarbonate formulated with conventional stabilizers after aging under hydrolyzing conditions.

In table II the data shows no reduction in oven heat aging properties using cadmium 2-ethylhexanoate.

In table III the data demonstrate that cadmium 2-ethylhexanoate imparts substantially similar optical and melt stabilities to those obtained using other commercial stabilizers. The samples prepared for table III were molded at two different temperatures 520° F. and 700° F. The variable Y is a measure of brightness and is better with the higher value. YI is the yellowness index, the closer the number is to zero the better the color of the polycarbonate article. Irradiation designates the brightness and yellowness after 310 hrs. after exposure of the polycarbonate article to sunlamp light. The samples for irradiation testing were molded between 540° and 570° F.

As is demonstrated by the above examples, cadmium organic salts provide enhanced hydrolytic stability to polycarbonates over conventional stabilizer without detrimentally effecting the other desirable physical properties for which polycarbonates are used.

A polycarbonate resin which was the reaction product of bisphenol A and phosgene having a melt flow rate at 300° C. of 6 to 12 g/10 min (ASTM 1238) was tumble blended with a copolycarbonate resin based on bisphenol A and tetrabromobisphenol A having 10 percent by weight bromine therein. The blended resin had a melt flow rate at 300° C. of 6 to 12 g/10 min. (ASTM 1238). Sufficient copolymer was used to impart 5% bromine to the total polycarbonate mixture. 0.1 percent by weight based on the weight of total polycarbonate and copolycarbonate resin of a 66% cadmium 2-ethylhexanoate solution was also tumble blended with the resins. The tumble blend was extruded and cut into pellets. The pellets were molded and tested for impact half-life testing. The impact half-life durability is the time taken during aging at 70° F. and 100% relative humidity for the sample to reach one-half of its original impact strength. The test results are reported on Table VI.

EXAMPLES XI and XII

Example X was repeated substituting the conventional stabilizers distearyl pentaerythritol diphosphite (Example XI) and tri (mixed mono and dinonyl phenyl) phosphites (Example XII). Test results are reported on Table VI.

Example X was repeated except no stabilizer was added to the polycarbonate. Test results are reported on Table VI.

______________________________________

IMPACT STRENGTH HALF-LIFE ON AGING AT 70° C.

WITH 100% RELATIVE HUMIDITY

Stabilizer

Half Life

Example Stabilizer Concn. (Days)

______________________________________

X cadmium 2-ethyl-

0.1 65

hexanoate

XI distearyl pentaery-

0.1 48.3

thritol diphosphite

XII tri (mixed mono and

0.1 56.8

dinonyl phenyl)

phosphites

XIII 87.1

______________________________________

As is demonstrated by Table VI cadmium 2-ethylhexanoate provides improved hydrolytic stability over conventional polycarbonate stabilizers. However, the cadmium 2-ethylhexanoate stabilized polycarbonate is worse in hydrolytic stability than the neat resin. It is necessary to add a stabilizer to the polycarbonate to provide protection from heat and light. The cadmium salts of the invention provide this protection to halogenated polycarbonate resins while imparting improved hydrolytic stability over conventional stabilizers.

______________________________________

______________________________________

Molecular

Molecular

Wt % PC Formula Wt

______________________________________

1. Cadmium 0.05 C.sub.16 H.sub.30 O.sub.4 Cd

398.74

2-ethylhexanoate

2. Cadmium Octoate

0.033 C.sub.16 H.sub.30 O.sub.4 Cd

398.74

3. Cadmium Laurate

0.042 C.sub.24 H.sub.46 O.sub.4 Cd

510.95

4. Cadmium Valerate

0.026 C.sub.10 H.sub.18 O.sub.4 Cd

314.58

5. Cadmium Myristate

0.047 C.sub.28 H.sub.54 O.sub.4 Cd

567.05

6. Cadmium Palmitate

0.052 C.sub.32 H.sub.62 O.sub.4 Cd

623.16

7. Cadmium Stearate

0.056 C.sub.36 H.sub.70 O.sub.4 Cd

679.32

8. Cadmium Acetate

0.015 C.sub.4 H.sub.6 O.sub.4 Cd

230.49

9. Zinc Octoate 0.035 C.sub.16 H.sub.30 O.sub.4 Zn

351.77

5.9 g of cadmium octoate was mixed with 4.1 g of phenyl diphenyl

phosphinite* and the combined mixture was heated to 100° C. for 1

hour. This mixture was used in compounding with polycarbonate.

10. 0.10% of a mixture of cadmium octoate and phenyl diphenyl

phosphinite (in 5.9/4.1 ratio)

11. 0.30% of a mixture of cadmium octoate and phenyl diphenyl

phosphinite (in 5.9/4.1 ratio)

12. The polycarbonate resin (MERLON M-50) which was utilized

for comparative testing was the reaction product of bisphenol A

and phosgene having a melt flow at 300° C. of 3 to 6 grams/10

min.

(ASTM D-1238) and having a natural color of 7.5. The additives

(1-11 above) were incorporated into the polycarbonate using a

dry blend/extrusion compounding technique.

The properties studied for comparison of effectiveness were:

(a) Impact retention at 105° C. (dry air aging) and at 82°

C. (180° F.)

aging in water;

(b) Critical thickness property loss during dry air aging at 105°

C.

and water aging at 82° C. (180° F.);

(c) Retention of tensile properties at 130° C. (dry air aging) and

at

82° C. (aging in water);

(d) Color retention between moldings at 520° F. and 700°

F.;

(e) Discoloration (measured by yellowness index changes) during dry

air aging at 130° C.

13. All of the additives were compounded with polycarbonate at the

same mol percent level.

______________________________________

*Phenyl diphenyl phosphinite was prepared from the reaction of phenyl

dichloro

phosphine and phenol in presence of TEA. The crude product obtained was

redistilled.

__________________________________________________________________________

EFFECT ON IMPACT PROPERTIES (NOTCHED) OF M-50 COMPOUNDED

WITH VARIOUS ADDITIVES DURING OVEN AGING AT 130° C. AND WATER

AGING AT 82° C.

Cadmium Cadmium Octoate/

2-ethyl-

Cadmium

Cadmium

Cadmium

Cadmium

Cadmium

Cadmium

Cadmium

Phenyl diphenyl

hexanoate

Laurate

Octoate

Valerate

Stearate

Palmitate

Acetate

Myristate

phosphinite

__________________________________________________________________________

Additive Wt %

0.05 0.042 0.033 0.026

0.056

0.052

0.015

0.047

0.059/

0.177/

0.041 0.122

Impact

Properties

Aged in Oven

at 105° C.

1/8" Notched

Izod ft lbs/in

(0 hr) 17.32

17.45

17.61

17.99

17.98

17.33

17.58

17.58

17.13

17.40

16.87

14.51

17.50

13.30

16.17

(8 hrs) 17.76

-- 17.74

-- 17.42

-- 12.44

-- 2.67 -- 2.10 2.41

-- 1.67

--

(16 hrs)

17.69

-- 17.37

-- 13.25

-- 7.37 -- 2.09 -- 1.99 1.92

-- 1.51

--

(24 hrs)

-- 16.86

-- 17.52

-- 16.99

-- 7.76 -- 17.12

-- -- 1.89

-- 1.17

(32 hrs)

17.24

-- 17.27

-- 12.36

-- 2.18 -- 2.09 -- 1.63 1.73

-- -- --

(64 hrs)

11.94

-- 7.77

-- 2.20

-- 1.84 -- 1.84 -- 1.42 1.63

-- -- --

(72 hrs)

-- 16.82

-- 12.30

-- 2.86

-- 2.00 -- 7.38 -- -- 1.66

-- 1.22

(128 hrs)

12.46

-- 2.57

-- 1.83

-- 1.60 -- 1.70 -- -- -- -- -- --

(144 hrs)

-- 3.48

-- 3.38

-- 2.43

-- 1.84 -- 2.20 -- -- 1.50

-- 1.14

(288 hrs)

-- 1.99

-- 2.07

-- 1.84

-- 1.66 -- 1.97 -- -- 1.60

-- 1.11

(670 hrs)

-- -- -- -- -- -- -- -- -- -- -- -- -- -- --

Water aged

at 82° C.

1/8" Notched

Izod ft lbs/in

(0 day) 17.32

17.45

17.61

17.99

17.98

17.33

17.58

17.58

17.13

17.40

16.87

14.51

17.50

13.30

16.17

(1 day) 17.71

17.84

13.18

18.06

3.39

1.76

7.95 1.30 1.36 17.80

1.07 1.34

16.40

0.21

1.50

(3 days)

17.84

12.43

17.11

17.32

0.60

1.15

1.02 0.94 1.36 19.27

0.60 0.58

2.86

0.24

0.99

(6 days)

18.08

12.66

17.42

17.69

1.02

0.94

-- 0.58 -- 2.20 -- -- 2.61

-- 0.79

(12 days)

17.53

12.25

17.24

12.48

0.55

0.81

-- 0.53 -- 1.86 -- -- -- -- 0.51

(24 days)

-- 12.76

-- 8.02

-- 0.53

-- -- -- 1.55 -- -- -- -- --

__________________________________________________________________________

__________________________________________________________________________

EFFECT ON CRITICAL THICKNESS PROPERTIES OF M-50 COMPOUNDED

WITH VARIOUS ADDITIVES DURING OVEN AGING AT 130° C. AND WATER

AGING AT 82° C.

Cadmium Cadmium Octoate/

2-ethyl-

Cadmium

Cadmium

Cadmium

Cadmium

Cadmium

Phenyl diphenyl

hexanoate

Laurate

Octoate

Valerate

Palmitate

Myristate

phosphinite

__________________________________________________________________________

Additive Wt %

0.05 0.042 0.033 0.026 0.052 0.047 0.059/

0.177/

0.041

0.122

Oven Aging at 105° C.

0 hr 212 207 202 187 182 182 167 152

4 hrs 202 202 145 135 135 120 110 110

8 hrs 150 160 137 132 122 112 112 <100

16 hrs 145 142 122 122 122 112 112 <100

32 hrs 142 137 135 122 122 102 102

64 hrs 132 125 115 112 105 100 <100

128 hrs 132 122 102 102 102 100 <100

Aged at 82° C. in H.sub.2 O

0 day 212 207 202 187 182 182 167 152

1 day 192 192 <120 <120 <100 <100 <100 <100

3 days 177 165 <100 105 <100 <100 <100 <100

6 days 177 172

12 days 172 167

__________________________________________________________________________

__________________________________________________________________________

Water Aged (82° C.) Tensile Properties of Polycarbonates

Compounded with Various Cadmium Salts and Zinc Salts of Organic Acids

Cadmi-

um 2-

Cadmi- Cadmium Octoate/

ethyl-

um Phenyl

hexa-

Octo-

Zinc Cadmium

Cadmium

Diphenyl Cadmium

Aged Additive noate

ate Octoate

Laurate

Acetate

Phosphinite Stearate

__________________________________________________________________________

Additive Wt. % 0.05

0.033

0.035

0.041

0.015

0.059/0.041

0.177/0.123

0.059/.041

0 Days

Initial Tensile Properties

US Tensile Strength at Yield, psi

9300

9,300

9,000

9300 9,100

9,200 9,200 9,300

SI Tensile Strength at Yield, MPa

64.1

64.1

62 64.1 62.7 63.4 63.4 64.1

US Ultimate Tensile Strength, psi

9300

8,600

9,200

8000 9,100

9,800 9,500 9,200

SI Ultimate Tensile Strength, MPa

64.1

59.3

63.4 55.2 62.7 67.6 65.5 63.4

US Tensile Strength, Failure, psi

9100

9,200

9,200

9300 9,000

9,800 8,900 9,100

SI Tensile Strength, Failure, MPa

62.7

63.4

63.4 64.1 62 67.6 61.4 62.7

Elongation, Yield %

8 9 5 8 9 8 8 8

Ultimate Elongation %

105 40-105

110 100 100 114 25-118

100

3 Days

(72 hours)

US Tensile Strength at Yield, psi

9400

11,700

10,300

9500 9,800

9,000 -- --

SI Tensile Strength at Yield, MPa

64.81

80.7

71 65.5 67.6 62

US Ultimate Tensile Strength, psi

9400

11,700

10,700

9500 9,800

9,000 11,400

11,400

SI Ultimate Tensile Strength, MPa

64.81

80.7

71 65.5 67.6 62 78.6 78.6

US Tensile Strength, Failure, psi

8000

10,500

7,000

8000 7,300

6,800 -- 11,400

SI Tensile Strength, Failure, MPa

55.2

72.4

53.8 55.2 50.3 46.9 78.6

Elongation, Yield %

8 6 6 7 6 5 -- --

Ultimate Elongation %

9-30

8 40-100

8-40 15-35

10-50 10 4

6 Days

(144 hours)

US Tensile Strength at Yield, psi

-- -- -- 9600 10,200

9,200 -- --

SI Tensile Strength at Yield, MPa

66.2 70.3 63.4

US Ultimate Tensile Strength, psi

9400

12,300

9,500

9600 10,200

9,200 12,000

9,600

SI Ultimate Tensile Strength, MPa

64.81

84.8

65.5 66.2 70.3 63.4 82.7 66.2

US Tensile Strength, Failure, psi

9400

12,300

9,500

7100 8,400

6,600 -- 9,600

SI Tensile Strength, Failure, MPa

64.81

84.8

65.5 49 58 45.5 66.2

Elongation, Yield %

-- -- -- 7 8 5 -- --

Ultimate Elongation %

7 6 2 8-90 8-60 6 5 4

12 Days

(288 hours)

US Tensile Strength at Yield, psi

9300

-- -- 10,200

10,000

-- --

SI Tensile Strength at Yield, MPa

64.1

US Ultimate Tensile Strength, psi

9100

10,600 9700 10,200

10,000

10,500

4,600

SI Ultimate Tensile Strength, MPa

62.7

73 Samples

66.9 70.3 69 72.4 3

US Tensile Strength, Failure, psi

9000

10,600

Cracked

9700 8,400

9,100 10,500

4,600

SI Tensile Strength, Failure, MPa

62 73 66.9 58 62.7 72.4 31.7

Elongation, Yield %

8 -- 5 8 -- --

Ultimate Elongation %

7 6 5-80 6-12 3 3

24 Days

(576 hours)

US Tensile Strength at Yield, psi

-- -- -- 9800 10,800

10,000

-- --

SI Tensile Strength at Yield, MPa

67.5 74.5 69

US Ultimate Tensile Strength, psi

9400

5,500

3,100

9800 10,800

10,000

4,700 1,200

SI Ultimate Tensile Strength, MPa

64.81

38 21 67.5 74.5 32 8.3

US Tensile Strength, Failure, psi

9400

5,500

3,100

9000 9,700

9,100 -- 1,200

SI Tensile Strength, Failure, MPa

64.81

38 21 62 67 62.7 8.3

Elongation, Yield %

5 2 -- 6 5 5 -- --

Ultimate Elongation %

-- -- 1 1 8 6 1 1

__________________________________________________________________________

__________________________________________________________________________

Dry Air Aged (130° C.) Tensile Properties of Polycarbonates

Compounded with Various Cadmium Salts

and Zinc Salts of Organic Acids

Cadmium- Cadmium

2-Ethyl-

Cadmium

Zinc Cadmium

Cadmium

Octoate/Phenyl

Cadmium

Aged Additive Hexanoate

Octoate

Octoate

Laurate

Acetate

Diphenyl

Stearateite

__________________________________________________________________________

Additive Wt. % 0.05 0.033

0.035

0.041

0.015

0.059/

0.177/

0.056

0.041

0.152

0 Days

Initial Tensile Properties

US Tensile Strength at Yield, psi

9,300 9,300

9,000

9,300

9,100

9,200

9,200 9,300

SI Tensile Strength at Yield, MPa

64.1 64.1 62 62 62.7 63.4 63.4 64.1

US Ultimate Tensile Strength, psi

9,300 8,600

9,200

9,300

9,100

9,800

9,500 9,200

SI Ultimate Tensile Strength, MPa

63.4 59.3 63.4 64.1 62.7 67.6 65.5 63.4

US Tensile Strength, Failure, psi

9,100 9,700

9,200

9,000

9,000

9,800

8,900 9,100

SI Tensile Strength, Failure, MPa

62.7 66.9 63.4 62 62 67.6 61.4 62.7

Elongation, Yield %

8 9 5 8 9 8 8 8

Ultimate Elongation %

105 40-105

110 100 100 114 25-118

105

3 Days

US Tensile Strength at Yield, psi

10,800

11,400

11,400

10,900

11,000

10,400

10,900

11,600

SI Tensile Strength at Yield, MPa

74.5 78.6 78.6 75.1 75.8 71.7 75.1 80

US Ultimate Tensile Strength, psi

10,900

11,400

11,400

10,900

11,000

10,400

10,900

11,600

SI Ultimate Tensile Strength, MPa

75.1 78.6 78.6 75.1 75.8 71.7 75.1 80

US Tensile Strength, Failure, psi

9,800 9,100

8,800

9,900

11,000

10,400

10,900

11,600

SI Tensile Strength, Failure, MPa

67.6 62.7 60.7 68.3 75.8 71.7 75.1 80

Elongation, Yield %

5 5 6 5 5 8 5 5

Ultimate Elongation % 40-60 7-60 75-105

80-105

50-110

5-35

6 Days

US Tensile Strength at Yield, psi

10,300

10,800

10,600

10,300

10,600

10,600

11,200

10,600

SI Tensile Strength at Yield, MPa

71.1 74.5 73.1 71.1 73.1 73.1 77.2 73.1

US Ultimate Tensile Strength, psi

10,300

10,800

10,700

10,300

10,300

10,600

11,200

9,700

SI Ultimate Tensile Strength, MPa

73.1 74.5 73.8 71.1 71.1 73.1 77.2 66.9

US Tensile Strength, Failure, psi

8,600 7,800

9,700

7,600

8,300

8,000

7,600 8,600

SI Tensile Strength, Failure, MPa

59.3 53.8 66.9 52.4 57.2 55.2 52.4 59.3

Elongation, Yield %

8 7 4 6 4 10 5 4

Ultimate Elongation %

100 7-25 7-20 60-115

5-70 2-7

12 Days

Tensile Strength at Yield, psi

11,000

11,000

-- 11,000

12,200

11,400

-- --

Tensile Strength at Yield, MPa

75.8 75.8 -- 75.8 84.1 78.6 -- --

Ultimate Tensile Strength, psi

11,000

11,800

6,000

11,000

11,200

11,400

10,600

--

Ultimate Tensile Strength, MPa

75.8 81.4 41.4 75.8 77.2 78.6 73.1 --

Tensile Strength, Failure, psi

10,000

11,800

6,000

9,900

10,000

9,100

10,600

--

Tensile Strength, Failure, MPa

70 81.4 41.4 68.3 70 62.7 73.1 --

Elongation, Yield %

10 10 -- 10 5 8 -- --

Ultimate Elongation %

10-100

10 2 10-55

5-15 10-75

6 --

24 Days

Tensile Strength at Yield, psi

-- -- -- -- 10,700

11,300

-- --

Ultimate Tensile Strength, psi

9,700 3,900

1,050

9,800

10,700

11,300

Samples

2,700

Tensile Strength, Failure, psi

9,800 3,900

1,050

9,800

8,500

10,100

degraded

2,700

Elongation, Yield % 6 5 totally

Ultimate Elongation %

6 12 10

__________________________________________________________________________

__________________________________________________________________________

COLOR RETENTION AT 550° F. AND 700° F. MOLDINGS AS WELL AS

OVEN AGED AT 130° C.

550° F.

700° F.

6 days 12 days

24 days

Wt %

Y %

__________________________________________________________________________

% YI

.

Cadmiun 2-ethylhexanoate

0.05

88.23

3.3

88.26

3.3 88.39

4.9

87.17

10.4

88.06

6.0

88.47

3.6

88.52

4.0 88.02

4.1

88.37

4.1

88.26

4.5

Cadmium Laurate 0.042

88.01

3.7

87.77

6.4 88.11

5.2

-- -- 87.91

6.3

Cadmium 88.16

4.4

88.17

5.9 87.64

5.0

87.86

5.0

87.45

5.6

Cadmium Octoate 0.033

87.72

6.3

59.11

15.1 87.35

9.0

86.05

11.2

85.93

12.3

88.55

7.4

55.26*

61.6 87.81

9.1

86.81

11.2

85.82

14.9

Cadmium Stearate 0.056

88.46

9.4

42.91

13.4 Not aged since specimens show

a high

discoloration at 550°

F. and 700° F.

molding.

Cadmium Acetate 0.015

88.03

4.6

69.70

15.2 -- -- -- -- 87.73

7.4

Zinc Octoate 0.035

88.74

5.2

70.23

46.9 87.33

5.8

87.93

6.5

86.06

14.0

Cadmium Valerate 0.026

87.60

5.2

63.89

33.8 Since these compositions did

not exhibit

Cadmium Palmitate 0.052

87.83

8.3

63.76

41.4 retention of impact properties

during oven

Cadmium Myristate 0.047

87.86

7.5

65.38

33.2 and water aging, the optical

property aging

Cadmium Octoate/phenyl diphenyl phosphinite

0.059/

88.77

4.98

61.63*

48.96*

studies were not evaluated.

0.041

-- --

-- -- 87.80

4.62

88.07

4.5

87.24

5.7

Cadmium Octoate/phenyl diphenyl phosphinite

0.177/

82.47

68

(degraded)

0.123

-- --

-- -- 76.93

9.10

76.70

8.2

74.27

13.7

__________________________________________________________________________

*Exhibited splaying

700° F. molding with 1 min

550° F. molding with 35 secs cycle

From a review of the data of Tables VIII-XII, it can be noted that while several of the additives do, in fact, impart equivalent and at times superior properties to the polycarbonate composition in some tests than do the instantly claimed cadmium salts, only the instantly claimed polycarbonates containing cadmium 2-ethylhexanoate, cadmium octoate, cadmium laurate and cadmium acetate exhibit the best overall combination of tensile, impact and optical properties.

Although the invention has been described with reference to specific materials, the scope of the invention is only to be limited as is set forth in the accompanying claims.